Automatic sequencing burner control apparatus



J. W. SMITH Dec. 20, 1955 AUTOMATIC SEQUENCING BURNER CONTROL APPARATUS2 Sheets-Sheet 1 Filed May 23, 1952 7 lllllllllll II H Y mm M W S nfi mm w H m M u M v SP m m@ L m0 a u LIMIT CONTROL I 2,727,568 AUTOMATICSEQUENCING BURNER CONTROL APPARATUS Filed May 23, 1952 J. W. SMITH Dec.20, 1955 2 Sheets-Sheet 2 ON 0- 0 ON 0: 0Q Om Om ON 8 o 5.62 f f to 533mz? 20; E2

mzumo zoEQzoo we no INVENTOR. JAMES W SMITH ATTORNEY United StatesPatent AUTOMATIC SEQUENCING BURNER CONTROL APPARATUS Application May 23,1952, Serial No. 289,490 7 Claims. (Cl. 158-28) This invention relatesto an automatic sequencing fuel burner control apparatus in which anelectric timing motor and associated switch contacts are operative, whenthe timing motor is energized, to cause the components of a fuel burnerunit to operate in a predetermined sequence under the control of a powerfailure relay, which relay is normally continuously energized so long aspower is continuously supplied to the control apparatus.

it has been found that when an electronic flame detector is used tosupervise a burner flame, a time delay must be introduced after a powerfailure or after power is first supplied to the flame detector andbefore power is applied to the burner unit in an attemptto establish aflame at the burner. This is true since the electron discharge devicesof the flame detector when deenergized cool to an inoperative conditionand upon the restoration of power it is necessary that the abovementioned time delay Figure l is a schematic representation of theimproved burner control apparatus used in conjunction with an electronicflame detecting apparatus;

Figure 2 is a representation of the timing motor, the timing cams andthe associated switches; and

Figure 3 is a time diagram showing by means of a bar graph the intervalsduring which the switches of Figure 2 are in their closed or openedpositions.

Referring specifically to Figure l, a burner unit 10 is shown having arotary oil burner 11, a gas pilot assembly 12, and a photoelectric cell13 located so as to view a flame emitting from the rotary oil burner 11.A blower motor 14 is provided for the rotary oil burner 11 and a valve15 controls the supply of oil to the burner 11. The pilot burnerassembly 12 has associated therewith a spark electrode 16 connected bymeans of a conductor 17 to an ignition transformer 18. Also associatedwith the gas pilot assembly 12 is a flame rod 20 arranged, by means tobe later described, to detect the presence of a gas flame at the pilotassembly 12. A valve 21 is operative to control the supply of gas to thegas pilot assembly 12.

be provided so that the discharge devices of the flame detector willheat to their operative temperature rendering the flame detectorsensitive to the presence of flame before the control apparatus isconditioned to supply power to the burner control unit in an attempt toestablish flame at the burner.

It is therefore an object of the present invention to provide asequencing fuel burner control which is responsive to a power failure toprovide a timed cycle upon resumption of power allowing the electrondischarge devices of an associated flame detector to heat to anoperative temperature before the fuel burner is energized by thesequencing fuel burner control.

It is also an object of the present invention to provide an automaticsequencing fuel burner control apparatus normally providing apredetermined cycle of operation of a fuel burner unit upon a need foroperation of the unit but responsive to power failure to provide a firstcycle of operation wherein the burner unit is not energized, followed bya second cycle of operation wherein the fuel burner is energized whenthere is a need for operation or" a fuel burner.

It is a further object of the present invention to provide an automaticsequencing fuel burner control apparatus having a power failure relayand a timer interconnected such that as long as there is no powerfailure the timer provides a predetermined cycle of operation energizinga fuel burner under the supervision of a means responsive to the needfor operation of the burner, but that upon a power failure and therestoration of power, the timer motor provides the above-mentioned cycleof operation independently of the means responsive to the need foroperation of the burner without energizing the burner but momentarilycompletes an energizing circuit for the power failure relay and thenrecycles under control of the means responsive to the need for operationof the burner to provide the cycle'of operation energizing the fuelburner.

These and other objects of the present invention will be understood uponconsideration of the accompanying specification, claims, and drawings ofwhich:

Within the broken lines 22. is shown a program sequencing device whichwhen connected to the burner unit 10 is operative to energize thecomponents of the burner unit in a predetermined sequence of operation.Within the sequence device 22 is located a power failure relay 23 havinga relay winding 24, movable switch blades 25 and 26, and stationarycontacts 27, 28, and 29. The switch blade 25 is biased by means notshown to be out ofengagement with the contact 27 and to engage thecontact 28. Likewise the switch blade 26 is biased by means not shown tobe normally out of engagement with the contact 29. The broken lineposition of the switch blades 25 and 26 is the position the bladesassume when the relay winding 24 is energized.

A timer motor 30 is provided within the sequence device 22 to causeoperation of switches C1 through C10 located within the sequence device22. Referring to Figure 2, the timer motor 30 is shown with anassociated gear train 31 driving cams 32 through 41 and by means of thecontour of the'cams the switches C1 through C10 are controlled in apredetermined cycle of operation, shown in Figure 3, to effect apredetermined cycle of operation of the burner unit 10 as will bedescribed later.

Referring once again to Figure l, a relay 42 is provided within thesequencing device 22 which relay has a relay winding 43, switch blades44, 45, and 46, and associated switch contacts 47, 48, and 49. Theswitch blade 44 is normally biased by means not shown to be out ofengagement with the switch contact 47 and the switch blades 45 and 46are normally biased by means not shown to engage the switch contacts 48and 49 respectively. A relay 51 is also provided within the sequencingdevice 22, which relay has a relay winding 50, switch blades 52, 53, and54, and switch contacts 55, 56, and 57. The switch blades 52, 53, and 54are biased by means not shown to be out of engagement with the switchcontacts 55, 56, and 57 respectively.

Shown within the broken line 60 is a primary control device having acontrol relay 61, a safety cutout device 62, and a flame detector 63with its associated flame relay 64. The above mentioned relay 61 has arelay winding 65, associated switch blades 66, 67, and 68, and switchcontacts 69, 70, 71, and 72. The switch blades 66 and 68 are biased bymeans not shown to be out of engagement with the contacts 69 and 72respectively while the switch blade 67 is biased into engagement withcontact 71 and out of engagement with contact 70. The safety cutoutdevice 62 comprises a bimetal actuator 73, a bimetal heater 74, normallyclosed cutout contacts 75 and 76, and a-manual reset actuator 77. Theoperation of the safety cutout device 62 is such that when the bimetalactuator 73 is heated for a predetermined period of time by the heater74, the bimetal warps to the right out from under the cutout contacts'75 and 76 and these contacts disengage. it is then necessary tomanually depress the reset actuator 77 to reset the safety cutoutcontacts 75 and 76 so that they will again assume the position as shownin Figure l.

The flame detector 63 may be one of a variety of flame detectors whichsense a flame by sensing the rectifying properties of the flame or byutilizing a rectifying photocell viewing the flame. A flame detector ofthis type is shown in the John M. Wilson Patent 2,448,503. Associatedwith the flame detector 63 is a flame relay 64 arranged to be energizedupon the flame detector 63 sensing the presence of flame. The relay 64comprises a relay winding 8%, switch blades 81, 82, and 83, and switchcontacts 84, 85, and 86. The switch blade 81 is biased by means notshown to normally engage the switch contact 84 while the switch blades82 and 83 are biased by means not shown to normally disengage and 86respectively. The switch blades 81 and 32 overlap in their operation,that is, upon energization of the relay winding 88 the switch blade 82moves into engagement with the switch contact 85 before the switch blade81 disengages the switch contact A transformer 94 having a primary 95and a secondary 96 center tapped at 97 is arranged to supply power tothe circuits which include the relay 61 and safety cutout device 62.

For purposes of illustration a thermostat 87 located in the space to beheated by the burner unit is arranged to control the operation of theprimary control device and the program seq ence device 22 to establish aflame at the burner unit 19 upon there being a need for such operation.The thermostat 37 includes a bimetal actuator 88 which is effective tocomplete a circuit first from contact 89 to actuator 88 and then fromcontact 90 to actuator 88 upon there being a call for heat. A limitcontrol 91 is shown and may be one of a plurality of devices whichsenses an unsafe condition existing at the burner unit '10. For examplethe limit control 91 may be a device responsive to excessive hightemperature caused by prolonged energization of the burner unit 10 toopen an associated circuit when this high temperature is reached.

Operation At this point it will be assumed that power has been suppliedto power line conductors 92 and 93 for a considerable length of time andthe program sequence device 22 has operated in a manner to be explainedlater to energize the relay 23 and to return the timer motor 3.0 to itsstarting position. It will further be assumed that the thermostat 87 isnot calling for operation of the burner unit 10. Under theseassumptions, the device will be in the standby condition shown in Figurel with the switch blades and 26 of the relay 23 in the dotted lineposition. In other words, the switch blade 25 is disengaged from theswitch contact 28 and engages the contact 27 while the switch blade 26engages the contact 29. The energizing circuit for relay winding 24 canbe traced from power line conductor through conductor 103, power inputterminal 164, conductor 105, conductor 106, relay winding 24, conductor115, conductor 116, switch contact 29 and switch blade 26 of relay 23,conductor 117, conductor 118, conductor 112, and power input terminal113 to power line conductor 93. It can immediately be seen that therelay 23 will remain in its energized .condition so long as power iscontinuously applied to the power line conductors 92'. and 93, in otherwords, so long as there is no power failure. The relay 23 therefore be"comes a power failure relay since it will assume its deenergizedcondition upon the interruption of power at Y the power input terminals104 and 113.

An energizing circuit for the flame detector 63 can be traced from thepower line conductor 92 through conthe switch contacts 85 ductor 100,conductor 101, flame detector 63, and conductor 102 to the power lineconductor 93. Since it is assumed that power has been applied to theconductors 92 and 93 for a substantial length of time the electrondischarge devices of the flame detector 63 will be heated to theiroperative temperature at this time.

An energizing circuit can be traced for the primary 95 of thetransformer 94 within the primary control device 60 from the power lineconductor 92 through conductor 10!), conductor 120, primary 95,conductor 121, conductor 122, switch contact 27 and movable switch blade25 of relay 23, conductor 111, conductor 112, and power input terrnnial113 to power line conductor 93.

Assume now that there is a call for heat and the thermostat actuator 88moves to engage the contacts 89 and 90. An energizing circuit can now betraced for the relay 61 within the primary control device 60 from theupper terminal of the secondary 96 through conductor 123, relay winding65, conductor 124, contacts 89 and of thermostat 87, conductor 125,contact C8 of the program sequence device 22, conductor 126, conductor127, contact 84 and switch blade 81 of relay 64, conductor 128, contacts75 and 76 of safety cutout device 62, conductor 1 29, heater 74, andconductor to the lower terminal of the secondary 96. it will be notedfrom tracing the above circuit that it is necessary for-the timer motor30 to be in its start position such that contact C8 is closed as shownin Figures 2 and 3.

Immediately upon the relay 61 being energized the movable switch blade66 moves into engagement with the switch contact 69 and establishes anenergizing circuit for the relay 61 which is independent of the timercontact C8. This circuit can be traced from the upper terminal of thesecondary 96 through conductor 123, relay winding 65, conductor 124,contact 89 and actuator 88 of thermostat 87, conductor 131, contact 69and movable switch blade 66 of relay 61, conductor 132, conductor 127,contact 84 and movable switch blade 81 of relay 64, conductor 128,contacts 75 and '76 of safety cutout device 62, conductor 129, heater74, and conductor 130 to the lower terminal of the secondary 96.

Energization of the relay 61 also causes the movable switch blade 67 tomove into engagement with the contact 70 and to disengage contact 71.This completes a first contact in a holding circuit for the relay 61,however, this holding circuit is not completed until the relay 64 isenergized to indicate the presence of flame, as will be described morefully. Energization of the relay 61 also causes the movable switch blade68 to engage the contact 72 and this completes a circuit from a terminal133 to a terminal 134 of primary control device 60, which terminals areconnected by conductors 135 and 136 respectively to terminals 137 and138 respectively of the sequence device 22.

The movement of switch blade 68 to engage contact 72 completes anenergizing circuit for the relay 51 of the sequence device 22which canbe traced from the power line conductor 92 through conductors 103, 105,107, 140, 141, winding 50 of relay 51, conductor 142, terminal 137,conductor 135, terminal 133, switch blade 68 and contact 72 of. relay61, terminal 134, conductor 136, terminal 138, conductor 143, limitcontrol 91, conductor 144, conductor 145, conductor 122, contact 27and-movable switch blade 25 of relay 23, conductor 111,

conductor 112, and power input terminal 113 to power line .copductor-93. It can immediately be seen that this energizing circuit for relay51 depends upon the limit contr ol being in its circuit closingposition.

Energization of the relay 51 causes the switch blade 54 to move intoengagement with the contact 57. This completes an energizing circuit forthe blower motor 14 of the rotary oil burner 11. This circuit can betraced from the power line conductor 92 through conductor 146, motor 14,conductor 147, terminal 148, conductor 1 49, conductor 150, switch blade54am! contact 57 of relay 51, conductor 151, conductor 145, conductor122, switch contact 27 and switch blade 25 of relay 23, conductor 111,conductor 112, and power input terminal 113 to power line conductor 93.It will be noted that this energizing circuit for the blower motor 14 ofthe rotary oil burner 11 depends upon the power failure relay 23 beingin its energized position such that switch blade 25 engages contact 27.Energization of the relay 51 also causes the movable switch blade 53 tomove into engagement with the stationary contact 56 and the movableswitch blade 52 to move into engagement with stationary contact 55. Thiscompletes an initial energizing circuit for the timer motor 30 which canbe traced from the power line conductor 92 through conductor 103, powerinput terminal 104, conductor 105, conductor 107, timer motor 30,conductor 152, contact 48 and movable switch blade 45 of relay 42,conductor 153, switch blade 53 and contact 56 of relay 51, conductor154, conductor 155, conductor 156, contact 55, and movable switch blade52 of relay 51, conductor 157, conductor 145, conductor 122, contact 27and movable switch blade 25 of relay 23, conductor 111, conductor 112,and power input terminal 113 to power line conductor 93. It will againbe noted that this energizing circuit for the timer motor 30 isdependent upon the relay 42 being deenergized, the relay 51 beingenergized, and the power failure relay 23 being energized.

The cycle of operation has now been initiated since the timer motor 30is energized. Referring to Figures 2 and 3, the cams 32 through 41 areshown in their start position and, as indicated, rotate in acounter-clockwise direction upon energization of the timer motor 30 tocontrol the associated switches C1 through C respectively. The closedposition of the switches is shown in Figure 3 by the black bars of asshown in Figure 3.

Closing of the contact C1 establishes a holding circuit for the timermotor 30. This holding circuit can be traced from the power lineconductor 92 through conductor 103, conductor 105, conductor 107, timermotor 30, conductor 188, conductor 158, contact C1, conductor 159,conductor 112, and power input terminal 113 to power line conductor 93.It can be seen from this above traced circuit that the energization ofthe timer motor 30 is no longer dependent upon the relay 42 beingdeenergized, the relay 51 being energized, and the power failure relay23 being energized. Referring to Figure 3, it can be seen that thecontact C1 remains closed until the run condition is reached, which isafter the timer motor has run for 120 seconds. At this time the contactC1 opens this above traced holding circuit for the timer motor 30.

ductor 92, through conductor 146, motor 14, conductor 147, terminal 148,conductor 149, contact C4, conductor '1, conductor 145, conductor 122,contact 27 and switch blade 25 of relay 23, conductor 111, conductor112, and power input terminal 113 to power line conductor 93.

and the power failure relay 23 for approximately 15 seconds after thethermostat 87 has been satisfied and opens its circuit to cause theburner unit 10 to be deenergized in a manner to be explained later.

The opening of the contact C8 after the timer motor has operated forapproximately five seconds opens the above traced initial energizingcircuit for the relay 61. However, as pointed out above, the relay 61 ismaintained energized through a circuit which includes the switch blade66 and the contact 69 of the relay 61.

The timer motor 30 continues to operate for an additional 15 secondsuntil contact C3 completes an energizing circuit for relay 42 which canbe traced from power line conductor 92 through conductor 103, powerinput terminal 104, conductors 105, 107, 140, 202, winding 43 of relay42, conductor 203, conductor 205, contact C3, conductor 156, contact 55and switch blade 52 of relay 51, conductor 157, conductor 145, conductor122, contact 27 and switch blade 25 of relay 23, conductor 111,conductor 112, and power input terminal 113 to The energization of relay42 causes switch blade 44 to move into engagement with contact 47. Thiscompletes a holding circuit for relay 42 around contact C3 since switchblade 44 and contact 47 are in shunt with contact C3.

Energization of relay 42 also causes the switch blade 46 to disengagethe contact 49, to perform a function later to be described, and causesthe switch blade 45 to disengage the contact 48. This disengaging ofcontact 48 opens the above traced initial energizing circuit for timermotor 30, however, it will be remembered that timer motor is nowenergized by means of a holding circuit under the control of contact C1.

The timer motor continues to operate until it has operated a total ofapproximately ductor 103, input terminal 104, conductors 105, 107, 140,141, 160, terminal 161, conductors 162, 163, 164, ignition transformer18, conductor 165,'terminal 166, conductor 167, contact C7, conductors168, 169, 142, terminal 137, conductor 135, terminal 133, switch blade68 and contact 72 of relay 61, terminal 134, conductor 136, terminal138, conductor 143, limit control 91, conductors 144, 145, 122, contact27 and movable switch blade 25 of relay 23, conductor 111, conductor112, and input terminal 113 to the power line 93. It will be noted thatthe energizing circuit for the ignition transformer 18 is dependent uponthe power failure relay 23 being energized. Th

The

interval between 22 and 30 seconds provides a pre-ignition period.

At 30 seconds the contact C5 closing of the contact C5 completes annects the flame electrode 20 to the flame detector 63 can be traced fromthe flame detector 63 through conductor 175, contact C10, conductor 176ignition electrode 20, gas conduit 177, ground connection 178, andground connection 179 to the flame detector 63. When flame isestablished at the pilot burner 12, the relay 64 will be energized bythe flame detector 63.

The opening of the contact C6 at the 30 second point opens theenergizing circuit of the oil valve when the flame detector 63 detects aflame at the pilot assembly 12, which circuit will be traced later. Thesystem is now operating such that the blower motor 14 is energized, theignition transformer 18 is energized and a flame is established anddetected at the pilot burner 12.

Referring particularly to the primary control device 69, energization ofthe flame relay 6 causes the switch blades 81, S2, and 83 to move totheir operative position. The engagement of switch blade 82 with contact85 completes an energizing circuit for the relay 61 which is independentof the safety cutout device 62. This energizing circuit can be tracedfrom the upper terminal of the secondary 96 through conductor 123, relaywinding 65, conductor 1224, contact 89 and actuator 88 of thermostat 87,conductor 131, contact 69 and switch blade 66 of relay 61, contact 70and switch blade 67 of relay 61, conductor 1%, switch blade 82 andcontact 85 of relay 64, and conductor 181 to the. center tap 97 of thetransformer 96. The switch blade 81 then disengages the contact 84 ofthe relay 64 to break the initial energizing circuit for the relay 61.Energization of the relay 64 also causes the switch blade 83 to engagethe switch contact 86 and thereby complete a circuit from the terminal132 to the terminal 183 to perform a function later to be described.

Referring again to Figure 3, it can be seen that the timer operates foran additional seconds, or from the second to the 5.0- second period, toprovide a period during which the flame is established at the pilotassembly 12 and detected by the flame detector 63. After the timer motor30 has been energized for a total of seconds the contact C5 opens andthe contact C6 closes. Normally the opening of the contact CS woulddeenergize the valve 21 controlling the flow of gas to the pilot burnerassembly 12. However, the detection of the pilot burner flame has causedthe relay 64 to be energized and therefore a holding circuit isestablished for the valve 21. This holding circuit can be traced fromthe power conductor 92 through conductor 1G3, terminal 104, conductors1'95, 167, 14%, 141, 160, terminal 161, conductors 162, 163, 21,conductor 171, terminal 172, 185, terminal 187, conductor 188, 86 andmovable switch blade 83 182, conductor 193, terminal 133, 63 and,contact 72 of relay 61, terminal 134, conductor 136, terminal 138,conductor 143, limit control 91, conductors 144, 145, 122, terminal 27and switch blade 25' conductors 173, 184, terminal 183, contact of relay64, terminal of relay 23, conductors 111, 112, and input terminal 113'to power line 93.

The closing of C6 after the timer motor 36 has been energized for atotal period of 50 seconds energizes the oil valve 15 and allows oil toflow to the rotary oil burner 11.. The energizing circuit for the valve15 can be traced from the power. line 92 through conductor 103, inputterminal 1M, conductors 165, 167, 140, 141, 160-, terminal 161,conductor 162, conductor 192, valve 15, conductor 191, terminal 191),conductor 189, contact C6, conductor 186, conductor 185, terminal 187,conductor 183, terminal 183, contact. 36 and switch blade 83 of relay64, terminal 182, conductor 1 93, terminal 133, switch blade 86 andcontact 72 of relay 61, terminal 134, conductor 136, terminal 138,conductor 143, limit control 91, conductor 14.4, conductor 145,conductor 122, contact 27 and switch blade 250i relay 23, conductor111', conductor 112;, and input terminal 113 .to power line 93.

The apparatus is now, operating with the blower motor- 14. and oil valve15 associated withv rotary oil. burner-.11 energized, with-the, gasvalve211 associated with the pilot burner: assembly, 1 2;energized, andwith the ignitiorrtrans= movable switch blade 170, valve 7 contact C7 isopen, contact conductor 180, switch blade 67 and former 18 energized. Aflame is now established at the rotary oil burner 11.

This flame. at the oil burner 11 is detected by the photoelectric. cell13 which is connected in parallel with the flame electrode 20. Thecircuit from the flame detector 63 through the photoelectric cell 13 canbe traced from the flame detector 63 through conductor 175, conductor194,, photoelectric cell 13, and conductor 195 to the flame detector 63,After the timer motor 36 has been energized for approximately 5.5seconds the contact C10 opens to break the circuit from the flamedetector 63 to the flame electrode 20. The flame detector 63 howeverremains energized with the photoelectric cell 13 supervising the flameat the. rotary oil burner 11. Therefore the relay 64 remains energizedso long, as a flame is maintained at the rotary oil burner 11.

The apparatus is now operating with the blower motor 14 and oil valve 15associated with the rotary oil burner 11 energized, with the gas valve21 associated with the pilot burner assembly 12 energized, with theignition transformer 18., energized, and. the flame detector 63supervising the flamev at the rotary oil burner 11 by means of thephotoelectric cell 13.

After the timer motor 30 has been energized for approximately 106seconds the contact C7 opens. The openingof contact C7 deenergizes. theignition transformer 18 by. opening its above traced. energizingcircuit.

After a total of, approximately 111 seconds of operation of the timermotor 30 the contact C2 closes. The closing of contact C2v conditions acircuit for energizing the timer. motor 30 which is effective to. returnthe timer motor to its starting position after the thermostat 87 opensto indicate that. there, is no longer a need for operation of the,burner unit- 10. This will bev explained in detail later.

After atotal of seconds of operation of the timer motor 30, the, contactC1v opens to deenergize the timer motor and stopthe, cams 32 through 41such that contact C1 is open, contact C2, is, closed, contact C3 isopen, con tact C4 is closed, contact C5 is open, contact C6 is closed,C8 is open, contact C9 is open, and contact C10. is open- This conditionwill exist as long as the thermostat 87. indicates that there is a needfor operation of the, burner unit 1.0.

Assume now. that the thermostat 87 has been satisfied and that theconnection from the contact 59 to the actuator 83 of the thermostat 87is broken. The relay 61 of the primary control device 66 is thereforedeenergized. The deenergization of the relay 61 causes the movableswitch. blade 68 to. disengage from contact '7 2 of the relay 6'1 andthereby immediately breaks the energizing circuit for the oil'valve15and the valve 21. The flame at both the rotary oil burner 11. and pilotassembly 12 is therefore extinguished.

Againreferring specifically to the primary control device 60, itwill beremembered that the absence of flame in the burner unit'10 normallycauses the flame relay 64 to be deenergized. Assume for the sake ofexplanation that a fault has occurred. in the flame detector 63' and therelay 64 does not become deenergizedwhen a flame is extinguished at theburner unit 10. An energizing circuit, also known as a componentchecking circuit, can now be traced for the heater 74 of the safetycutout device 62' from thecenter tap 97 of the secondary 96 throughconductor 181, contact 85' and switch blade 82 of relay 64, contact 71of relay 61, conductor, 200, heater 74-; and conductor to the lowerterminal of'the secondary 96. After this condition has existed for apredetermined length of'time, the bimetal 73 will warp to the right outfrom under tl e contacts 75 and 76 and these-contactswill disengage. Inthis condition it is impossible for the-thermostatdl to initiateoperation of thesystem-since-the-initial energizing circuit for therelay 61 is-brolt'en'; It can-also be seen-that the heater 74 willremain energizeduntil the fault-is corrected within the=flame detector63? After this fault-has been corrected the relay 64 and therefore theheater 74 will be deenergized. After a predetermined length of time thebimetal 73 will cool and depressing of the manual actuator 77 will resetthe safety cutout contacts 75 and 76 to their engaged position.

Assume now that the flame detector 63 has operated in a normal mannerand has deenergized the relay 64. The switch blades 81, 82, and $3 ofthe relay 64 will return to their deenergized position and the entireprimary control 60 will now be as shown in Figure 1.

The deenergization of the relay 61 due to the thermostat 87 openingcauses the relay 51 to be deenergized. The switch blades 52, 53, and 54-of the relay 51 therefore assume their deenergized position. This breaksthe above traced energizing circuit for the relay 42 and breaks theinitial energizing circuit for the burner motor 14. However, the burnermotor 14 is maintained energized through the contact C4 as abovedescribed.

The deenergization of the relay 42 causes the switch blades 44, 45, and46 to return to their deenergized position. When the switch blade 46engages the contact 49 as it returns to its deenergizedposition, anenergizing completed from the power timer motor 30, 152, switch blade 46and contact 49 of relay 42, contact C2, conductor 201, conductor 112,and power input terminal 113 to power line conductor 93.

Referring to Figure 3, it can now be seen that the timer motor will beeffective to run for a total period of 20 seconds after the runningperiod. After the timing motor 3t) has been energized for approximately12 seconds the contact C3 closes. The closing of contact C8 conditionsthe initial energizing circuit for the relay 61 to be effective when thethermostat 87 again closes to call for operation of the burner unit 10.This 12 second interval is a part of the post-purge time since duringthis 12 seconds the blower motor 14 is energized. It should be notedthat during this 12 second interval the relay 61 cannot be reenergizedupon a call for heat since its initial energizing circuit is broken atC3.

After approximately 15 seconds of operation the contact C4 opens todeenergize the motor 14 and the contact C9 closes to perform a functionwhich will be described later.

If it is assumed that the thermostat 87 again calls for heat before the15 second interval is reached, it can be seen that switch blade 54 andcontact 57 of relay 51 will shunt contact C4 and hold the motor 14energized. With this assumption the motor 14 continues to run and whenthe timer motor 30 reaches the start position the burner unit is againenergized as above described.

After approximately 18 seconds of operation the contact C9 opens and thecontact C10 closes. Closing of the contact C10 connects the flameelectrode 20 to the flame detector 63 in preparation for another callfor operation of the burner unit 10 by the thermostat 87. At the end ofthe 20 second interval the timer motor has returned to the startposition as indicated in the left hand side of the diagram of Figure 3and is deenergized by the opening of contact C2.

Operation upon power failure The apparatus of Figure 1 is once again inits standby condition ready to produce another cycle of operation of theburner unit 10 upon a call for heat by the thermostat 87. It will beremembered that in this condition the power failure relay 23 isenergized and the movable switch blades 25 and 26 are at the broken linepositions shown in Figure 1. Assume now that there is a power failuredue to a condition external to the showing of Figure 1 and thereforepower is no longer applied to the power line conductors 92 and 93.

This interruption of power will have two eifects on the apparatus.First, the flame detector 63 will be deenerpower failure relay 23therefore assume their full line positions of Figure 1. Assume now thatpower is restored to the power line conductors 92 and 93.

if an attempt is now cannot be energized because the contact C9 is openand the switch blade 26 does not engage the contact 29 of relay 23.However, an energizing circuit for the timer motor 3t? can be tracedfrom the power line conductor 92 through conductor 103, power inputterminal 104, conductor 105, conductor 107, timer motor 30, conductor108, conductor 110, contact 28 and switch blade 25 of relay 23,conductor 111, conductor 112, and power input terminal 113 to the powerline conductor 93. The timer motor will therefore begin to rotate andwill cause the cams 32 through 41 of Figure 2 to operate the associatedswitches as shown in the graph of Figure 3. It will be noted that theenergizing circuit for the timer motor is dependent upon the powerfailure relay 23 being in its deenergized position.

When the timer motor has run for a period of approximately 5 seconds thecontact C1 will close, the contact C4 will close and the contact C8 willopen. The closing of contact C1 establishes a holding circuit for thetimer motor 369 which shunts the switch blade 25 and contact 28 of thepower failure relay 23. This holding circuit can be traced from thepower line conductor 92 through conductor 103, power input terminal 104,conductor 105, conductor 107, timer motor 30, conductor 108, conductor1.53, contact C1, conductor 159, conductor 112, and power input terminal113 to power line conductor 93. It will be remembered that the closingof the contact C4 normally energizes the blower motor 14 of the rotaryoil burner 11. However, the energizing circuit for the motor 14 requiresthat the switch blade 25 of the power failure relay 23 engage thecontact 27, as shown in the broken line position of Figure 1. Therefore,the motor 14 is not energized. The opening of the contact C8 breaks theinitial energizing circuit for the relay 61 of the primary controldevice 60 to insure that a call for heat by the thermostat 87 does notenergize the relay 61. Since the energizing circuit for the primary ofthe transformer 9 located within the primary control device 60 requiresthat the movable switch blade 25 engage the contact 27 of power failurerelay 23 it is also impossible at this point to energize the relay 61because the transformer 94 is not energized.

The timer motor will continue to run causing operation of the contactsC1 through C10, however, it will be remembered that none of thecomponents of the burner unit 10 will be energized since the energizingcircuits for any one of these components such as valves 15 and 21,

ignition transformer 18 or blower motor 14 require that the switch blade25 engage the contact 27 of the power failure relay 23, or in otherwords, that the power failure relay be energized. After the timer motor30 has run for a peeriod of seconds the contact C1 will open. Thisnormally deenergizes the timer motor in the run position, however theenergizing circuit for the timer motor 30 which includes the contact 28and the switch blade 25 of relay 23 is still completed and the contactC2 has been closed to complete a second energizing circuit for the timermotor. This second circuit can be traced from the power line conductor92 through conductor 103, power input terminal 104, conductor 105,conductor 107, timer motor 30, conductor 152, switch blade 46 andcontact 49 of relay 42, contact C2, conductor 201, conductor 112, andpower input terminal 113, to power line couductor 93. Under normalrunning conditions this last traced circuit is not etfective at thispoint since the relay 42 is energized and the above traced circuit isbroken at switch blade 46 which normally at this point in the cycle doesnot engage. the contact 49 of relay 42..

After the timer motor has run for an additional 12 seconds or a total of132 seconds the contact C8 will close to condition the initialenergizing circuit of the relay 61 to be completed upon a call for heatby the thermostat 87. However, if the thermostat 87 is calling for heatat this time the relay 61 will not be energized since the transformer 94remains deenergized due to the power failure relay 23 being deenergized.After an additional 15 seconds of operation or a total of 145 seconds,the contact C9 closes to complete an energizing circuit for the powerfailure relay 23. This circuit can be traced from the power lineconductor 92 through conductor 103, power input terminal 104, conductor105, conductor 106, relay winding 24, conductor 115, contact C9,conductor 118', conductor 112, and power input terminal 113 to powerline conductor 93. The relay 23 will now be energized and the switchblades 25 and 26 will move to engage contacts broken line positions ofFigure 1. The energization of relay 23 at this point causes primary 95of transformer 94 to be energized.

It is perhaps desirable at this point to reconsider what has taken placeafter the restoration of power to the power line conductors 92 and 93.First of all, the electron discharge devices of the flame detector 63are energized as soon as power is restored to the power line conductors92 and 93, and these electron discharge devices begin to heat and aftera predetermined length of time reach an operative temperature to placethe flame detector 63 in a condition to detect a flame. Second, thetimer motor is immediately energized upon restoration of power and iseffective to control the contacts C1 through C10 in the predeterminedcycle. However, the burner unit 10 is not energized since the powerfailure relay remains in its deenergized condition. After the timermotor has operated for 135 seconds the power failure relay 23 isenergized through a circuit which includes the contact C9 which isclosed by the timer motor 30. It can therefore be seen that the electrondischarge devices of the flame detector 63 have a period of 135 secondsin which to heat to their operative temperature to condition the flamedetector 63 to detect flame. It is well at this point to explain afurther desirable feature of the device of Figure 1 in that should afault occur in the flame detector 63 and cause the relay 64 to beenergized upon the electron discharge devices of the flame detectorbeing heated to their operative temperature and thereby falsely indicatethe presence of flame, the initial energizing circuit for the relay 61is now broken since the switch blade 81 disengages the contact 84 of therelay 64, which switch blade and contact are in the initial energizingcircuit of relay 61. Also, as above explained, the heater 74 of thesafety cutout device 62 is energized since the relay 61 is in itsdeenergized condition and the relay 64 is in its energized conditionfalsely indicating the presence of flame. After a predetermined lengthof time the safety cutout device 62 will be actuated to insure that therelay 61 cannot be energized.

Consider once again the condition of the apparatus of Figure 1 after thetimer motor has run for a period of 135' seconds. If the thermostat S7is not calling for heat, the timer motor 30 will continue to beenergized through a circuit which can be traced from power lineconductor 92 through conductor 103, power input terminal 104, conductor105, conductor 107, timer motor 30, conductor 1S2, switch blade 46 andcontact 49 of relay 42, contact C2, conductor 201, conductor 112, andpower input terminal 113 to power line conductor 93. Referring to Figure3 it can be seen that this energizing circuit is completed until thecontact C2 opens after the timer has run for a total period of 140seconds and the timer is again at the start position such that theapparatus of Figure 1. is conditioned upon a call for heat by thethermostat 87 27 and 29 respectively as shown in the 12 to provide thenormal cycle of operation of the burner unit If there is now a call forheat by the thermostat 87 the apparatus of Figure 1 will cycle theburner unit 10 in the normal manner to produce a flame at the rotary oilburner 11. It can therefore be seen that the present invention providesa sequential oil burner control which is normally effective to cycle aburner unit in a predetermined manner and which is effective after apower interruption to provide a time delay before the burner unit can beenergized thereby insuring a safe start of the burner unit.

For purposes of explanation, assume now that there was a call for heatby the thermostat 87 during the power failure or during the first 135seconds of operation of the timer motor 30 after the restoration ofpower. When the timer motor 30 reaches the 135 second point in its cycleof operation the power failure relay 23 will be energized as abovedescribed and the burner unit 10 will be conditioned to be energized bythe contacts controlled by the timer motor 30. Also, the primary 95 ofthe transformer 94 located within the primary control device will beenergized. Relay 61 will therefore be energized and switch blade 68 willengage contact 72 of relay 61. An energizing circuit for the relay 51 ofthe sequence device 22 can now be traced from the power line conductor92 through conductor 103, power input terminal 104, conductors 105, 107,140, 141, winding 50, conductor 142, terminal 137, conductor 135,terminal 133, switch blade 68 and contact 72 of relay 61, terminal 134,conductor 136, terminal 133, conductor 143, limit control 91, conductor144, conductor 145, conductor 122, contact 27 and switch blade 25' ofrelay 23, conductor 111, conductor 112, and power input terminal 113 topower line conductor 93.

The energization of the relay 51 causes the blower motor 14 to beenergized through a circuit which can be traced from the power lineconductor 92 through conductor 146, motor 14, conductor 147, terminal148, conductor 149, conductor 1150, switch blade 54 and contact 57 ofrelay 51, conductor 151, conductor 145, conductor 122, contact 27 andswitch blade 25 of relay 23, conductor 111, conductor 112, and powerinput terminal 113 to the powerline conductor 93.

At this point within the cycle the energization of the relay 61 does notcause the valves 15 or 21 or the ignition transformer 18 to be energizedsince the associated timer contacts are open and the flame relay 64 isin its deenergized condition. The timer will therefore continue to run,with blower motor 14 energized, until the start position is againreached, however, the timer motor 30 will not stop in the start positionsince the energization of the relay 51 completed the initial energizingcircuit for the timer motor 30 and the motor continues to operate in itsnormal cycle to control the burner unit 10 in the normal manner.

Power failure during a normal start Now assume, for purposes ofexplanation, that the timer motor 30 is somewhere within the startingcycle, for example, the second point in its cycle of operation.Referring to the previous discussion of the normal operation of theapparatus of Figure 1, it will be remembered that the control motor 30is now energized through a circuit which includes the contact C1, andthe valves 15 and 21 and the ignition transformer 18 areenergizedthrough energization. circuits which include various contactscontrolled by the timer motor, with all of the encrgizing circuits beingunder the master control of the power failure relay 23 with the switchblade 25 engaging the contact 27. Assume that there now is a powerfailure.

The power failure relay 23 power failure by assuming its deenergizedposition with the switch blades 25 and 26 assuming their full lineposition of'Figure 1.

will immediately sense this,

The energizing Qireuits for the valves 15 and 21 and the ignitiontransformer 18 will be immediately broken so that the restoration ofpower will not reenergize these components of the burner unit '10. Therestoration of power now, whether after a momentary interruption orafter a prolonged interruption of power, will cause the timer motor 30to continue its rotation until the contact C9 is closed at which .timethe power failure relay 23 will again be energized and upon a continuedcall for heat by the thermostat 87 the control motor v30 will recyclewhen it reaches the start position to again establish flame at theburner unit 10. With the assumption made that the power failed at the 70second interval it can be seen that the electron discharge devices ofthe flame detector 63 will have from the 7.0 second interval to the 140second interval to be heated to their operative temperature, or in otherwords, 70 seconds. This is more than adequate time for the dischargedevices of the flame detector 63 to become operative such that the abovementioned component checking circuit of the primary control device 60 iseffective to insure that the flame detector 63 is operating in theproper manner.

The shortest time interval which the apparatus of Figure 1 provides as atime delay after a power failure occurs when power fails during therunning period of the burner unit 10. In this case the interruption ofpower immediately causes flame to be extinguished at the burner unit 10and if there is still a call for heat when power is retored, the timermotor runs for an additional second interval and then recycles to againestablish flame at the burner unit 10. This 20 second interval has beenselected as the shortest allowable time to provide safe operation of theapparatus of Figure 1.

It can therefore be seen that I have provided an improved automaticburner control apparatus wherein the timer motor which providesautomatic sequential operation of the components of a fuel burner unitis also effective after a power failure to insure a safe start of theburner unit. It will be recognized that this broad feature of noveltymay take many different forms other than that shown in Figure l and thatthe time intervals expressed in Figure 3 may be adjusted for the mostdesirable operation of a particular burner installation.

Having thus described my invention I claim:

1. A burner control apparatus for use with a fuel burner unit,comprising: a source of power, a relay having a coil and switchingmeans, a circuit including said source of power and said relay coil fornormally energizing said coil, said relay switching means assuming afirst position when said coil is energized or a second position whensaid coil is deenergized, timing means including an actuator andswitching means, terminal means adapted to be connected to a fuel burnerunit, circuit means including said source of power and controlled bysaid relay switch means and said timing means switching means andeffective when completed to supply power to said terminal means, a firstenergizing circuit for said timing means actuator controlled by saidrelay switch means in said first position to provide a first cycle ofoperation of said timing means wherein power is supplied to saidterminal means, a second energizing circuit for said timing meansactuator controlled by said relay switch means in said second positionconnecting said timing means actuator directly to said source of powerto provide a second cycle of operation of said timing means whereinpower is not supplied to said terminal means, and means controlled bysaid timing means during said cycle of operation to complete anenergizing circuit for said relay coil thereby completing said firstenergizing circuit for said timing means actuator causing said timingmeans to provide said first cycle of operation wherein power is suppliedto said terminal means.

2. A burner control apparatus for use with a fuel burner unitcomprising: terminal means adapted to be connected to a fuel burnerunit, a relay having an aceffective tuator, a circuit normallyenergizing said relay actuator, a timer having an actuator and timeroperated switching means, circuit means controlled by said timeroperated switching means normally effective when the actuator thereof isenergized to supply power to said terminal means, means cont-rolled bysaid relay for preventing said circuit means from supplying power tosaid terminal means when said relay actuator is deenergized, a firstcircuit for normally energizing said timer actuator in response to ademand for burner operation, means controlled by said relay forpreventing said first circuit from being established except when saidrelay actuator is energized, a second circuit for energizing said timeractuator upon deenergization of said relay regardless of the demand forburner operation, and means rendered effective by said timer operatedswitching means when said timer actuator is so energized forreenergizing said relay actuator to permit normal operation of saidtimer in response to a demand for burner operation.

3. A programming fuel burner control apparatus, comprising: power inputterminals adapted to be connected to electrical power lines, a timerhaving a timer motor and a plurality of switches controlled thereby in apredetermined cycle of operation from a starting condition, fuel burnerterminal means adapted to be connected to a fuel burner, circuit meanscontrolled by said plurality of switches connecting said fuel burnerterminal means to said power input terminals, an energizing circuit forsaid timer motor including said power input terminals and includingterminals adapted to be connected to means responsive to the need foroperation of the fuel burner, said energizing circuit being completedupon a need for fuel burner operation, means operative upon a powerfailure to cause said circuit means to be rendered into connect saidfuel burner terminals to said power input terminal means, meansoperative upon a power failure to cause said timer to cycle to saidstarting condition upon the restoration of power independent of a needfor operation of the fuel burner, and means to cause said circuit meansto remain ineffective to connect said fuel burner terminal means to saidpower input terminals until said timer approaches said startingcondition.

4 A burner control apparatus comprising a source of power, a powerfailure relay having a coil and a plurality of switches, a first and asecond of. said switches being in circuit closing position only whensaid coil is energized, a third of said switches being in circuitclosing position only when said coil is deenergized; circuit meansincluding said first relay switch connecting said relay coil directly tosaid source of power whereby said relay coil is maintained energized solong as a power failure does not occur; a timer having an actuator and aplurality of switches operated in a predetermined sequence through acycle of operation from a start position, a first of said timer switchesmoving to circuit closing position substantially immediately uponenergization of said aetuator, a second of said timer switches moving tocircuit closing position after said timer has substantially completedits cycle of operation; fuel burner terminal means adapted to beconnected to a fuel burner, terminals adapted to be connected to meansresponsive to the need for operation of the fuel burner, circuit meansincluding said last named terminals adapted to energize said timeractuator upon a need for fuel burner operation, circuit means adapted toconnect said fuel burner terminal means to said source of powerincluding said second relay switch and further switches of said timerwhich are closed during said cycle of operation of said timer wherebysaid fuel burner terminal means are connected to said source of poweronly when said relay coil is energized and said timer has moved fromsaid start position; circuit means including said third relay switchadapted to connect said timer actuator directly to said source of powerupon a power failure occurring to cause said timer to operate through acycle of operating wherein said fuel burner terminal means are notconnected to said source of power, and circuit means including saidsecond timer switch adapted to connect said relay coil directly to saidsource of power after said first cycle has been substantially completedto thereby reenergize said relay coil.

5. A burner control apparatus for use with a fuel burner unit,comprising: a power failure relay having an actuator and switchingmeans, a circuit including said actuator normally rendering said relayoperative so long as power is supplied to said control apparatus,terminal means adapted to be connected to a fuel burner unit, a timerhaving a timing motor and a plurality of switches controlled thereby,circuit means controlled by certain of said last named switches and bysaid relay switch means to supply power to said terminal means, saidrelay switch means conditioning said circuit means to supply power tosaid terminal means only when said relay is energized; a firstenergizing circuit for said timing motor controlled by said relay switchwhen said relay is energized and including means responsive to the needfor operation of the fuel burner unit to thereby provide a first cycleof operation of said timing motor wherein power is supplied to saidterminals, a second energizing circuit for said timing motor completedby said relay switch means when said relay is deenergized to provide asecond cycle of operation of said timing motor wherein power is notsupplied to said terminal means, and a means controlled by a furtherswitch controlled by said timing motor during its cycle of operation tocomplete an energizing circuit for said relay whereby said relay isenergized and said first energizing circuit for said timing motor isconditioned to be completed by the means responsive to the need foroperation of the burner.

6. A burner control apparatus for use with a fuel burner unit,comprising: terminal means adapted to be connected to a fuel burnerunit, a timer having a timer motor and switch means controlled therebyand being arranged to provide sequential operation of a fuel burner unitby supplying power to said terminal means, power input terminals, apower failure relay having an actuator, an energizing circuit connectingsaid relay actuator to said power input terminals, said timer switchmeans being arranged to momentarily complete said energizing circuit ata given time during the operation of said timing motor, first switchmeans controlled by said relay actuator to complete a holding circuitfor said relay actuator to said power input terminals when said relayactuator is energized to thereby maintain said relay actuator energized,second switch means controlled by said relay actuator having a firstposition when said actuator is energized and having a second positionwhen said actuator is deenergized; terminals adapted to be connected tomeans responsive to the need for operating the fuel burner unit, a firstenergizing circuit for said timer motor including said last namedterminals and including said second relay switch means in said firstposition, whereby said timer motor is energized upon a need foroperation of said fuel burner unit and said second relay switch meansbeing in said first position, and a second energizing circuit for saidtimer motor including only said second relay switch means in said secondposition whereby said timer motor is energized upon said second relayswitch means being in the second position.

7. A burner control apparatus to provide a predetermined operation of afuel burner assembly, comprising: power input terminals adapted to beconnected to a power source, a timer having a plurality of switches andan actuator arranged when energized to control said switches in apredetermined cycle of operation, burner assembly terminal means adaptedto be connected to a fuel burner assembly, circuit means controlled byat least one of said timer switches for supplying power to said burnerassembly terminal means; a power failure relay including an actuator andthree switches controlled thereby, a self holding circuit for said relayactuator connecting said relay actuator to said power input terminalsand completed by a first of said relay switches upon said relay actuatorbeing energized; means connecting a second switch controlled by saidrelay actuator in controlling relation to said circuit means, saidsecond switch enabling power to be supplied under the control of saidone timer switch to said burner assembly terminal means only when saidrelay actuator is energized; a normal energizing circuit for said timeractuator controlled by said second relay switch and including meansresponsive to the need for operation of the fuel burner assembly, saidnormal energizing circuit being arranged to energize said timer actuatorwhen said relay actuator is energized and there is a need for operationof the fuel burner assembly, an energizing circuit for said timeractuator including a third switch controlled by said relay actuator toconnect said timer actuator directly to said power input terminals whensaid relay actuator is deenergized by momentary power failure to therebyprovide a first cycle of operation of said timer wherein power is notsupplied to said burner assembly terminal means, and a further switch ofsaid plurality of switches of said timer effective at a given timeduring said first cycle of its operation to momentarily complete anenergizing circuit connecting said relay actuator to said power inputterminals whereby said relay is energized to enable power to be suppliedto said burner assembly terminal means as said timer recycles upon acontinued need for operation of the fuel burner assembly.

References Cited in the file of this patent UNITED STATES PATENTS

